1. Field of the Invention
The present invention relates to sleeping compartments for vehicles, and more particularly to a stowable step ladder for such compartments which may be compacted for stowage.
2. Description of the Problem
Fold down overhead beds and bunkbeds are a common response to the desire to provide sleeping accommodations in a compartment with limited space, such as found on railroad passenger trains and in long haul trucks. Ease of access to the upper berth or berths of a bunkbed, or to a fold down overhead bed, requires a ladder of some sort. Due to constraints of space, access to the berths is typically limited to one side of the berth and, for the convenience of the passenger, the ladder is preferably located along the same side of the bed, although in some cases steps and hand grips are built into cabinets located at one end of the berth. For the convenience of the lower berth occupant, and to save space, where ladders are used, they are preferably stowable. Making the ladder stowable is aided by making the ladder foldable or collapsible.
Volvo in its VN 770 series trucks provides a stowable ladder based on a parallelogram mechanism. The design stows cleanly and tightly, but uses gravity to aid opening. This means that the device can open for a tired user more quickly than expected or can fall open if a passenger loses his grip while the vehicle is moving. What is desired is a stowable ladder which can be opened with one hand, but which does not make use of gravity to unfold.